About Optics & Photonics TopicsOSA Publishing developed the Optics and Photonics Topics to help organize its diverse content more accurately by topic area. This topic browser contains over 2400 terms and is organized in a three-level hierarchy. Read more.

Topics can be refined further in the search results. The Topic facet will reveal the high-level topics associated with the articles returned in the search results.

Abstract

We present two silver nanocones separated by 450 nm, well beyond the typical gap spacing of coupled nanoantennas, and connected by a metal bridge to facilitate plasmonic coupling between them. The tip-enhanced Raman scattering from crystal violet molecules is found to be almost an order of magnitude higher from the bridged cones than from individual cones. This result is supported by local-field calculations of the two types of structures. The bridged nanocones are easily fabricated by a nanoimprint-based process, thus offering a faster and simpler approach compared to other fabrication techniques.

Figures (3)

FE-SEM images of the single (a) and bridged (b) nanocones structures with drawings depicting their dimensions included (insets). An illustration (c) of the orientation of the cones in the experimental setup is also given.

(color online) a) The emission spectra for the bridged nanocones (1) and single nanocone (2) in the presence of CV. The background signal (3), obtained by measuring from a point in the solution away from the cones, is given. b) The resulting Raman bands after the CV fluorescence background has been removed demonstrating the TERS enhancement improvement of the bridged nanocones (red) compared to the single nanocone (black).

Local field amplitude distribution simulations for three structures: single nanocone (a), two nanocones separated by 450 nm (b), and the bridged nanocones structure (c). The amplitudes were normalized to the maximum value of the focused beam without the structures. A 5-fold increase in field amplitude is observed at the tips of the bridged structure compared to single nanocones.